(CNN) -- U.S. military authorities have filed charges against seven soldiers accused of abusing Iraqi prisoners -- but that is only the beginning of the military prosecution process.

The military legal system is dictated by the Uniform Code of Military Justice, a federal law that sets the foundation of U.S. military law.

First, the accused person's commander recommends charges and forwards them to a special court-martial convening authority, usually a senior officer, according to David Sheldon, a military law expert and former military defense attorney. That officer, or authority, normally oversees the trial from beginning to end.

The authority reviews the material and orders a hearing -- known as an Article 32 hearing -- to determine if the charges merit a general court-martial.

Unless security concerns prohibit it, Article 32 hearings are open to the public, said Eugene Fidell of the National Institute of Military Justice.

At the hearing, similar to a civilian preliminary hearing, a legal officer decides whether the evidence is adequate to pursue charges. The prosecution and defense may call witnesses, and the accused may testify, but that is rare.

The legal officer then recommends whether the charges should be pursued or dropped, but the convening authority is not required to adopt the recommendation.

If the case does move to court-martial, the convening authority selects jurors and decides whether the accused will face a possible death penalty.

The jurors are officers and enlisted personnel, but the defendant can choose to be tried solely by a military judge.

There are different types of courts-martial, convened according to the severity of the charges:

A special court-martial -- military equivalent of a civilian misdemeanor court -- is used in less serious cases and requires only a jury of three.

A general court-martial is for felony-level offenses. It carries heavier sentences and requires a jury of at least five members. General courts-martial that carry a potential death penalty must have 12 jury members.

A summary court-martial governs petty offenses and has a one-officer court. This type of court-martial is becoming increasingly rare.

As in civilian court proceedings, the charges must be proved beyond a reasonable doubt in a court-martial, and defendants have the right to a lawyer, a jury trial and to question the evidence against them.

Not all jurors must agree in a military court. Imposing the death penalty demands a unanimous vote, but in most cases, conviction and sentencing require a two-thirds majority.

Jurors, called panel members in a court-martial proceeding, vote by secret ballot. While mistrials are possible in a court-martial, it is impossible to have a hung jury that would allow a new trial. If the government fails to obtain the required two-thirds majority, the defendant is acquitted.

Sentencing is conducted by the jury. Unlike in civilian courts that often have mandatory minimum sentences, a jury can impose zero punishment on a conviction in a court-martial.

Also unlike in civilian courts, in cases that carry multiple charges, only one sentence is returned for a guilty verdict in a court-martial.

Guilty verdicts in a general court-martial are subject to automatic review, Fidell said.

The justice code also allows the U.S. president to prescribe the procedures for courts-martial.

The president's rules have to "apply the principles of law and the rules of evidence" recognized in the civilian justice system. The president's instructions are detailed in an executive order known as the Manual for Courts-Martial.